The present invention relates to a device for driving and damping telescopic guards of the type consisting of a plurality of box-shaped elements.
Guards of this kind are used mainly to protect the slideways of automatic machines, machine tools and robotized system by preventing dirt, chippings, swarf and machining emulsions from getting into and clogging up the contact areas of the slideways.
The latest machines run at increasingly higher speeds and it is therefore becoming more and more important to keep the slideways clean and in perfect working order at all times.
The box-shaped elements are fitted with scrapers, usually, made of an elastomer or plastic material. These scrapers, besides keeping dirt and other foreign matter out of the gaps between adjacent box-shaped elements, also permit the achievement of a satisfactory seal.
Since the guard is connected to the moving part of the machine, the box-shaped elements extend and retract at the same speed as that at which the machine moves. This speed can be very high and considering their size and weight, the box-shaped elements, when they reach the fully extended position, knock against each other with considerable force. Such shocks must obviously be avoided not only because of the wear and eventual damage they cause to the guard but also to prevent counterblows on the moving machine parts and, last but not least, to reduce noise.
It is therefore essential to provide damping devices between the box-shaped elements.
A damping device designed for this purpose is described in utility model patent publication DE-U-7137781. In this publication, the damping device is made by simply applying to the back of the scraper, where it comes into contact with the smaller, adjacent box-shaped element a strip of synthetic cellular material. Another type of damping device for the box-shaped elements of a telescopic guard made from a strip of material different from that of the scraper is described in patent publication EP-B-290822.
However, with damping devices of this kind, shocks are still possible on account of the high speeds reached by the moving machine parts, the weight of the boxshaped elements and the limited deformability of the strips of synthetic material.
Moreover, when the guards reach the fully extended position, the box-shaped elements stop, passing from a very high speed to zero speed in a very short space of time. They are therefore subjected to a high deceleration rate which can have negative effects on the moving machine parts.
Italian patent No. 012862248, in the name of the same Applicant as the present, describes a damping device equipped with deformable, elastic arms designed to damp the impact between two adjacent box-shaped elements when these are being extended.
Mechanical devices designed to simultaneously open all the box-shaped elements making up the telescopic guards have also been made in an attempt partly solve the problem of shocks. These devices consist either of a series of chains acting on hooking elements located in each single box-shaped element or complex telescopic joints located in the box-shaped elements themselves.
The principal aim of the present invention is to overcome the disadvantages of prior art through a new device for driving and damping the box-shaped elements of telescopic guides that is capable of simultaneously driving all the box-shaped elements while providing a gradual and effective damping action and that is simple and economical to make.